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I A Nimmo

Publications and source records attributed to I A Nimmo.

At least 19 recordsLinked to original sources
PubMed1991

The major glutathione S-transferase in salmonid fish livers is homologous to the mammalian pi-class GST.

1. The hepatic glutathione S-transferase (GST) isoenzymes were isolated and characterized from salmon, sea trout and rainbow trout. 2. In all three species the predominant GST expressed comprised subunits of Mr 24,800. These subunits each co-migrated with the rat pi-class Yf polypeptide during SDS/polyacrylamide gel electrophoresis. 3. Western blotting experiments demonstrated immunochemical cross-reactivity between the major salmonid and the rat pi-class GSTs. 4. The salmon GST of subunit Mr 24,800 was digested with cyanogen bromide and the peptides, once purified by reverse-phase HPLC, were subjected to automated amino acid sequencing. 5. Over the region sequenced, the salmon GST possessed about 65% homology with the rat and human pi-class GST.

Amino Acid Sequence↗
PubMed1987

The human glutathione S-transferase. Studies on the kinetic, stability and inhibition characteristics of the erythrocyte enzyme.

Bromosulphophthalein and N-ethylmaleimide, inhibitors of glutathione S-transferase (EC 2.5.1.18 RX: glutathione R. transferase), have been used to identify variant forms of the erythrocyte enzyme. One 'atypical' sample was detected and was shown to have appreciably different kinetic and stability properties. These inhibitors may be useful in surveys of variation in this group of enzymes.

Adult↗
PubMed1986

Studies on the relationship between glutathione S-transferase phenotype and bile acid binding by human liver cytosol.

The possibility that the GST1 phenotype of human liver cytosol is a determinant of bile salt binding has been investigated by using equilibrium dialysis and gel-exclusion chromatography. Binding of bile salts was non-saturable and whereas the glutathione S-transferases did not appear to be major bile salt binders, other binding components with molecular weights of 35 000 and 11 000 were identified in both fetal and adult cytosols.

Adult↗
PubMed1986

The glutathione S-transferase activity in the pyloric caeca of rainbow trout, Salmo gairdneri.

Pyloric caeca of trout contain 1.9 mmol GSH/kg tissue. Cytosolic glutathione S-transferase activity with 1-chloro-2,4-dinitrobenzene as substrate is 0.06 mmol/min/g protein. Cholate (3.3 mM) inhibits cytosolic transferase activity by 55% at pH 6.6 and by 4% at pH 7.4. The transferases do not bind 8-anilino-1-naphthalene sulphonate at pH 7.4. The cytosolic transferases are inactivated progressively by 1-chloro-2,4-dinitrobenzene, 50% of their activity being lost in 5.0 min. A minority of the activity does not bind to a glutathione-affinity matrix. At pH 6.6 its apparent Michaelis constants for GSH and 1-chloro-2,4-dinitrobenzene are 0.88 and 9.1 mM respectively. The rest of the activity is eluted from the affinity matrix as a single peak. Its apparent Michaelis constants for GSH and 1-chloro-2,4-dinitrobenzene are 0.33 and 2.9 mM respectively. Its subunit Mr is 22.4 kDa.

Animals↗
PubMed1986

Purification and properties of the hepatic glutathione S-transferases of the Atlantic salmon (Salmo salar).

Salmon from salt water have three classes of soluble hepatic glutathione S-transferases which can be separated from cytosol by affinity chromatography and chromatofocusing. The classes have different substrate specificities and kinetic properties. All the enzymes are dimeric proteins. There are immunologically distinct subunits of Mrs 22.4, 23.0 and 24.0 kDa. Fish killed in August have enzymes with different apparent isoelectric points and subunit compositions than fish killed in February. The glutathione S-transferase activity of fresh-water salmon is similar to that of February salt-water fish except that the former binds less avidly to S-hexylglutathione-Sepharose 6B.

Amino Acids↗
PubMed1985

The glutathione S-transferase activity in the kidney of rainbow trout (Salmo gairdneri).

Trout kidney contains 2.3 mmol GSH/kg. The cytosolic glutathione S-transferase activity with 1-chloro-2,4-dinitrobenzene as substrate is 0.35 mumol/min/mg protein. There is no detectable activity with 1,2-epoxy-3-(p-nitrophenoxy)propane, ethacrynic acid, p-nitrobenzyl chloride or p-nitrophenyl acetate. A variable proportion of the activity does not bind to a glutathione-affinity matrix. Its Km values for GSH and 1-chloro-2,4-dinitrobenzene are 3.0 and 5.1 mM, respectively. The rest of the activity is eluted from the affinity matrix as one main and two minor peaks. The main peak has Km values for GSH and 1-chloro-2,4-dinitrobenzene of 0.4 and 4.5 mM, respectively. Its subunit Mr is 22,900. The activity in the main peak is inhibited progressively by 1-chloro-2,4-dinitrobenzene with a rate constant of 0.11/min.

Animals↗
PubMed1984

The substrate specificities and subunit compositions of the hepatic glutathione S-transferases of rainbow trout (Salmo gairdneri).

Chromatofocusing separated the glutathione S-transferases of trout liver cytosol into species termed cationic (eluted from pH 8-5) and anionic (eluted by 1.0 M NaCl at pH 5). The cationic enzymes were separated from cytosol by S-hexylglutathione affinity chromatography, ultrafiltration and chromatofocusing (pH 9-7) into 4 major (C1, C2, C4 and C5) and 3 minor fractions. The anionic material was not purified in this way because only 50% of the activity bound to the S-hexylglutathione column. The major cationic enzymes had similar half-saturation concentrations for GSH (0.2 mM) and 1-chloro-2,4-dinitrobenzene (0.4 mM); those of the anionic material were higher (0.7 mM, 1.9 mM respectively). The substrate specificities of the cationic enzymes C1 and C2 were similar (e.g., conjugation of bromosulphophthalein) as were those of C4 and C5 (e.g., conjugation of 1,2-epoxy-3-(p-nitrophenoxy) propane). The anionic material had a different specificity (e.g., rapid conjugation of p-nitrobenzyl chloride). SDS-polyacrylamide gel electrophoresis showed C1 and C2 to be homodimers of subunit Mr 22,400, C4 to be a heterodimer (Mr's 22,400 and 24,500), and C5 predominantly an Mr 22,400 homodimer.

Animals↗
PubMed1984

Distribution and some properties of bile salt-binding proteins in rainbow trout, Salmo gairdneri.

Trout liver cytosol has proteins that bind bile salts and 8-anilino-1-naphthalene sulphonate and that co-elute from Sephadex G-75. The binding of 8-anilino-1-naphthalene sulphonate is decreased by 90% in the presence of 33 microM lithocholate, implying the proteins are the same. Bile salt-binding protein is present in liver, but was not detected in gills, kidney, muscle or intestine. Bile salt-binding protein, partially-purified by Sephadex G-75 chromatography, was resolved into 2 fractions by cholate-affinity chromatography. Fatty acids do not appear to be bound by bile salt-binding protein. No fatty acid-binding protein was detected in trout liver cytosol.

Animals↗
PubMed1983

The purification of the hepatic glutathione S-transferases of rainbow trout by glutathione affinity chromatography alters their isoelectric behaviour.

1. The basic glutathione S-transferases from rainbow-trout liver were more stable than the acidic ones. 2. The apparent pI values of these enzymes were lowered when they were eluted from a glutathione affinity column by reduced glutathione at pH 8.85. 3. The pI effect was not a function of the high pH alone, was diminished under conditions less favourable to glutathione oxidation, and did not occur when S-hexylglutathione affinity chromatography was used instead.

Animals↗
PubMed1983

Distribution and some properties of the glutathione S-transferase and gamma-glutamyl transpeptidase activities of rainbow trout.

1. Gills, kidney, intestinal caeca and liver of trout have glutathione S-transferase activity with 1-chloro-2,4-dinitrobenzene (200 500 nmol/min/mg protein), and reduced glutathione (0.5 2.0 mmol/kg tissue). 2. Only kidney and intestinal caeca have substantial gamma-glutamyl transpeptidase activity with gamma-glutamyl-rho-nitroanilide (2-9 nmol/min/mg protein). 3. Renal gamma-glutamyl transpeptidase is membrane-bound and has similar kinetic properties to its mammalian counterparts. 4. The data are consistent with the presence of a mercapturic acid pathway in trout.

Acyltransferases↗
PubMed1981

Clinical value of bile salt tests in anicteric liver disease.

Fasting and postprandial serum bile salt concentrations and intravenous glycocholate disappearance were studied in 20 patients with anicteric liver disease who had only minor abnormalities of conventional liver function tests. Abnormalities in the fasting or two hour postprandial conjugated cholate concentrations were found in all but one of the patients who had an abnormality in bilirubin concentration. In these patients, fasting and postprandial conjugated cholate concentrations were raised on average three and two times respectively above the upper limit of the reference range, while bilirubin concentration was raised only 50%. Postprandial conjugated cholate concentrations were also abnormal in two patients with normal bilirubin concentrations. Measurement of fasting and postprandial conjugated chenodeoxycholate concentration and intravenous glycocholate disappearance proved less informative than the fasting and postprandial conjugated cholate test. These results suggest that, where bilirubin concentrations are normal or only slightly raised, measurement of serum fasting and two hour postprandial conjugated cholate concentrations may prove helpful in the detection of minor abnormalities in hepatic anion transport.

Adult↗
PubMed1981

Distribution of glycocholate in blood from human fetuses and adults.

Glycocholate binding by plasma proteins and erythrocytes from fetal and adult blood has been studied, and the results have been used to derive a compartmental model of the distribution of glycocholate in blood. This model assumes that glycocholate is distributed between the aqueous phase, albumin binding sites, binding sites on other plasma proteins, and erythrocytes. Whereas glycocholate binding by albumin was saturable [fetal blood: dissociation constant (0.5 mM), concentration of binding sites (11.3 mumoles/g protein); adult blood: dissociation constant (0.42 mM), concentration of binding sites (20.1 mumoles/g protein)], binding by other plasma proteins was not. The association of glycocholate with erythrocytes appeared to be based on partitioning rather than binding of the bile salt to specific sites. The value of the partition coefficient was 6.0. The compartmental model indicates that, in fetal blood, 46% of the glycocholate is in free solution, and 37% is bound to albumin. In blood from adults, the corresponding values are 31% in free solution and 59% bound to albumin.

Adult↗
PubMed1980

The effect of age on the intravenous sodium glycocholate test.

The clearance of an injected dose of sodium glycocholate has been studied in a group of 23 control subjects who had no evidence of liver disease. A significant correlation was found between bile salt clearance and age. No significant difference was found between the bile salt clearance of male and female subjects. Data derived from a simple compartmental model indicated that decreased clearance of bile salt with age was not specifically related to degenerative changes in hepatocellular integrity, hepatic uptake of bile salts or bile flow.

Adolescent↗